Method, System and Control Device for Controlling a Compressed Air Controlled Brake System

ABSTRACT

The invention relates to a method for controlling a compressed-air-controlled brake system of a utility vehicle ( 3, 4 ), wherein a monitoring sensor (S) monitors whether the means for securing or positioning a vehicle part of the utility vehicle ( 3, 4 ), a cargo ( 6 ) of the utility vehicle ( 3, 4 ) or a cargo carrier ( 7, 10 ) which accommodates a cargo ( 6 ) of the utility vehicle ( 3, 4 ), which are provided in order to ensure a safe driving state of the utility vehicle ( 3, 4 ), are present and wherein the brakes (B) of the utility vehicle ( 3, 4 ) are actuated automatically if the monitoring sensor (S) detects that the means for securing or positioning the vehicle part, the cargo ( 6 ) or the cargo carrier ( 7, 10 ), which are provided in order to ensure a safe driving state of the utility vehicle ( 3, 4 ), are not present. The invention also relates to a system composed of a brake system control device for such a brake system and a monitoring sensor as well as a brake system control device for this purpose. C.)

The invention relates to a method for controlling a compressed-air-controlled brake system of a utility vehicle. The invention also relates to a system composed of a brake system control device for such a brake system and a monitoring sensor as well as a brake system control device for same.

In road traffic there is a need to avoid vehicle states which present a danger to persons and objects. A possible source of danger is an unsecured or poorly secured load of a vehicle. In the field of utility vehicles, i.e. lorries and trailers, particular securing and, in particular, locking mechanisms are therefore provided for securing loads. However, there is the risk of the corresponding locking mechanism not being used or not being used correctly, and in such cases the vehicle load is inadequately secured. This is the case, for example, if a rolling container which is located on a loading surface of the utility vehicle is not satisfactorily locked. In the case of tipper vehicles this presents a risk if the tipper vehicle drives with the tipper body raised.

In other cases, insecure driving states can occur in road traffic if certain vehicle parts are not positioned as provided. An example of this is an opened fuel tank flap. In the case of container chassis there is a risk of inadvertently driving with the chassis extended. In the case of chassis with an integrated lifting platform, the vehicle is frequently unintentionally driven with the lifting platform raised.

The invention is therefore based on the object of minimizing dangers in road traffic which can occur, for example, owing to inadequate securing of the load or incorrect positioning of vehicle parts. The invention is also based on the object of using simple means to provide a possible way of making the driver of the vehicle aware of such driving states, i.e. making the driver aware of particular situations.

This object is achieved by means of the invention specified in Claims 1, 2, 11 and 13 and 15. The dependent claims specify advantageous refinements of the invention.

The invention has the advantage that by means of a fully automatic function of the vehicle, which is integrated into a control device for a brake system, a potentially or currently unsafe driving state owing to unsatisfactory securing or positioning is detected and the vehicle is subsequently braked in order to work towards bringing about a safe state and to minimize possible dangers as a result of the lack of securement of the vehicle part or of the load. A driving state is understood to mean, in contrast to the stationary state, the state in which the vehicle is driving. The invention can, however, also already be effective in the stationary state.

The braking can be carried out in the form of light braking pulses in the sense of a warning signal for the driver or as a genuine braking which leads to a reduction in the velocity, or as a combination thereof. The invention has the advantage of leading to an improvement in the safety in road traffic with only low expenditure on equipment and, in particular, without the need for intervention by a human operator. In particular, there is no need for any separate valves which have to be controlled manually in order to activate the brake of the vehicle. In order to implement the invention, it is necessary to extend a brake system control device, for example in the form of a software extension, and to add a monitoring sensor, which permits a significant improvement in safety through comparatively low financial expenditure. In some cases, such sensors are already present in the vehicle, for example in tippers in the form of proximity switches on the tipper body which indicate the lowered position of the tipper body. In the stationary state of the vehicle, such sensors are used to lower the chassis during tipping by means of an electronic air suspension onto the buffers, referred to as the unloading level.

The invention is basically suitable for all types of utility vehicles, in particular motorized vehicles such as lorries with a loading surface and tippers, and all types of trailer vehicles, both with a loading surface and with a tipper body. Accordingly, a motorized vehicle, a trailer vehicle or a vehicle train which is formed from a motorized vehicle and one or more trailer vehicles are understood as a utility vehicle. The load carrier for accommodating a load can be embodied, for example, as a container which is to be arranged on a loading surface of the utility vehicle, or as a tipper body for bulk material.

A vehicle part, a load of the utility vehicle or a load carrier can be monitored by the monitoring sensor. All vehicle parts which require particular positioning or securing, for example extendable parts of container chassis, a fuel tank flap or a lifting platform arranged on the chassis or the tipper body already mentioned, are possible as vehicle parts.

Depending on the type of the utility vehicle, the monitoring sensor can be embodied differently. If a locking mechanism is provided for securing a load, such as, for example, in rolling containers or tipper bodies with a locking means, the monitoring sensor can advantageously be configured to monitor the satisfactory locking of the load carrier, which accommodates a load of the utility vehicle, prescribed for the sake of a safe driving state of the utility vehicle, with respect to the utility vehicle. In some applications, no locking means is necessary, such as, for example, in the case of certain tipper vehicles in which the tipper body is already held by its own weight. For such cases, the monitoring sensor can be advantageously configured to monitor the satisfactory positioning of the load carrier, which accommodates a load of the utility vehicle, prescribed for the sake of a safe driving state of the utility vehicle, with respect to the utility vehicle. It is also advantageous to embody the monitoring sensor in such a way that both the satisfactory positioning and the satisfactory locking are monitored.

Accordingly, the monitoring sensor can be embodied as a locking sensor or as a positioning sensor or as a combined locking/positioning sensor. According to one advantageous development of the invention, the monitoring sensor is arranged in or on the utility vehicle.

The monitoring sensor can be, for example, a mechanical switch, an inductive proximity switch, a pressure sensor or an optical sensor such as, for example, a photoelectric barrier. The monitoring sensor can either be connected directly to a control device via an electric line, or via a wireless data transmission link or a vehicle bus system such as, for example, a CAN bus. The monitoring sensor can also be part of another control unit or of a control device in the utility vehicle.

According to a further aspect, the invention relates to a method for controlling a compressed-air-controlled brake system of a utility vehicle, wherein in the driving state of the utility vehicle the brakes of the utility vehicle are activated automatically. In this context, at least at the start of the automatic activation of the brakes of the utility vehicle the activation of the brakes takes place in such a way that this activation can be perceived as a warning signal by the driver of the utility vehicle but the driving utility vehicle is not decelerated or is only decelerated insignificantly. This has the advantage that active intervention is not performed, or at least is not performed immediately, into the driving behaviour of the utility vehicle but instead the driver is firstly just warned by the activation of the brakes. The automatic activation of the brakes may be triggered here basically by any type of signal or operating state of the vehicle and, in particular, the brake system control device. Since there is only one warning signal, said signal can in principle be generated at any time in the case of a driving vehicle without having adverse effects on road safety. The warning signal can therefore be triggered, for example, in the case of detection of excessive leakage of the compressed air system or in the case of an excessively high velocity.

According to one advantageous development of the invention, the warning signal is generated by means of the automatic activation of the brakes of the utility vehicle as a result of the monitoring sensor detecting that the securing or positioning of the vehicle part, of the load or of the load carrier, provided for the sake of a safe driving state of the utility vehicle, has not occurred.

According to one advantageous development of the invention, at least at the beginning of the automatic activation of the brakes of the utility vehicle the activation of the brakes takes place in a pulsed fashion as a result of the detection of unsatisfactory securement. The pulsed activation takes place in such a way that the brake pressure is modulated to and fro between a lower pressure value and an upper pressure value, wherein the driving vehicle is not decelerated or is only decelerated insignificantly. Such pulsed activation of the brakes has the advantage that a warning signal which can be clearly recognized by the driver of the utility vehicle and can easily be differentiated from other vehicle movements is generated. In this context, a low selection can be made for the lower pressure value, for example zero bar or a low value which is different from zero. The lower pressure value can advantageously lie in the region of the response pressure of the brakes, for example at approximately 1.2 bar. The upper pressure value is selected such that as a result of the activation of the brakes “jolting” in the vehicle, which can be perceived by the driver, is generated, but said jolting does not lead to any appreciable deceleration of the vehicle. The upper pressure value can lie, for example, in the region of 2.5 bar. The frequency of the pulsed activation of the brakes can advantageously be 1 Hz.

According to one advantageous development of the invention, in the case of automatic activation of the brakes of the utility vehicle as a result of detection of unsatisfactory securement during a first time period, at the start of the automatic activation of the brakes the driving utility vehicle is not decelerated, or is only decelerated insignificantly, by the automatic activation of the brakes, and after the expiry of the first time period the driving utility vehicle is decelerated significantly by the automatic activation of the brakes. The deceleration of the utility vehicle after the expiry of the first time period can take place up to a predefined velocity value, i.e. a limited velocity, or up to the stationary state of the vehicle. The duration of the first time period may be, for example, 5 seconds. This way, chronological staggering can be implemented between the warning signal, i.e. the slight activation of the brakes, and the activation of the brakes which leads to significant deceleration of the vehicle.

Basically, the specified functions can already be effective in the stationary state of the utility vehicle. According to one advantageous development of the invention, the automatic activation of the brakes, which does not, or only insignificantly, decelerates the driving utility vehicle, is triggered at a velocity above a first minimum velocity. This has the advantage that at correspondingly relatively low velocities which are below the first minimum velocity, driving with unsatisfactory securement does not lead to triggering of automatic braking, with the result that, for example, a tipper with a raised tipper body can be moved at a correspondingly low velocity, for example on a building site.

According to one advantageous development of the invention, the automatic activation of the brakes, which significantly decelerates the driving utility vehicle, is triggered at a velocity above a second minimum velocity. The second minimum velocity is higher than the first minimum velocity. In this way, staggering with respect to the velocity can also be implemented as an alternative to or in addition to the previously specified chronological staggering. This permits extensive flexibility of the use of the invention in different types of utility vehicle and fields of use.

According to one advantageous development of the invention, the automatic activation of the brakes of the utility vehicle as a result of detection of unsatisfactory securement is suppressed at a velocity above a third minimum velocity. According to one advantageous development, the third minimum velocity can be higher than the second minimum velocity. According to one advantageous development, above the third minimum velocity only the part of the automatic activation of the brakes which significantly decelerates the vehicle is suppressed. The warning signal is retained here. As a result, possible unsafe driving states which can occur as a result of automatic activation of the brakes at a relatively high velocity can be avoided.

The first minimum velocity may be, for example, 10 km/h, the second minimum velocity can be, for example, 20 km/h and the third minimum velocity can be, for example, 40 km/h. According to one advantageous development of the invention, the values for the first, second and third minimum velocities, as well as the duration of the first time period, can be stored in a memory of the brake system control device, and therefore set.

According to one advantageous development of the invention, in the case of the automatic activation of the brakes of the utility vehicle as a result of detection of unsatisfactory securement the braking force is increased from an initial value to a final value with a transition function, wherein the final value is higher than the initial value. The transition function is advantageously configured in such a way that a chronologically relatively slow transition occurs which permits the driver of the utility vehicle to brake the utility vehicle in the desired way by means of his own operator control interventions. The transition function may be, for example, a function with a linear or progressive characteristic. According to one advantageous development of the invention, during the automatic activation of the brakes of the utility vehicle owing to the detection of unsatisfactory securement it is monitored whether the driver of the utility vehicle carries out activation of the brakes himself. If activation of the brakes by the driver is detected, the automatic activation of the brakes is aborted or at least interrupted for a certain waiting time period. This permits the driver of the utility vehicle to bring the utility vehicle to a standstill at the desired location under his own control, for example when a warning signal is detected.

An advantageous system according to the invention has a brake system control device for a compressed-air-controlled brake system of a utility vehicle and a monitoring sensor which is configured to monitor whether the securing or positioning of a vehicle part of the utility vehicle, of a load of the utility vehicle or of a load carrier which accommodates a load of the utility vehicle, provided for the sake of a safe driving state of the utility vehicle, has occurred. The control device has an electronic control unit which is connected by a signal input to the monitoring sensor. The control unit is configured to bring about automatic activation of the brakes of the utility vehicle if a triggering signal is received from the monitoring sensor at the signal input, which triggering signal indicates that the securing or positioning of the vehicle part, of the load or of the load carrier, provided for the sake of a safe driving state of the utility vehicle, has not occurred.

An advantageous brake system control device for such a system has the electronic control unit which is configured to bring about the automatic activation of the brakes of the utility vehicle, in particular if the triggering signal is received from the monitoring sensor at the signal input. The electronic control unit is configured to carry out the previously mentioned methods, for example by corresponding programming of the control software of the electronic control unit.

The invention will be explained in more detail below by means of exemplary embodiments and using drawings, in which:

FIG. 1—shows a utility vehicle having a loading surface, and

FIGS. 2 and 3—show a utility vehicle having a tipper body, and

FIG. 4—shows a system composed of a brake system control device and a monitoring sensor, and

FIG. 5—shows time profiles of the signal of the monitoring sensor and brake pressure.

In the figures, identical reference symbols are used for elements which correspond to one another.

FIG. 1 shows a utility vehicle which has a traction machine 4 and a trailer vehicle 3. The trailer vehicle 3 may be embodied, for example, as a tow bar trailer or as a semitrailer. A brake system control device 1, for example in the form of a trailer EBS system, is arranged on the trailer vehicle 3. An electronically controlled brake system which is distinguished by the fact that it carries out the complete pneumatic brake control in the trailer vehicle and is configured in particular to be able to activate the brakes of the trailer vehicle automatically when necessary, i.e. without a request by activation of the brake pedal by the driver, is referred to as an EBS system.

The trailer vehicle 3 also has a loading surface 5. A rolling container 7 in which a load 6 is arranged is arranged on the loading surface 5. The rolling container 7 is secured to the loading surface 5 by means of a locking mechanism 8, 9. The locking mechanism 8, 9 has a load-carrier-side locking element 8 and a trailer-vehicle-side locking element 9, which are detachably connected to one another.

FIGS. 2 and 3 show a utility vehicle 3, 4 which is embodied as a tipper. In this case, the trailer vehicle 3 does not have a loading surface 5 but instead has a tipper body 10 which can be raised on one side by means of a, for example, hydraulically activated telescopic mechanism 11, and as a result tipped. FIG. 2 shows the utility vehicle 3, 4 with the tipper body 10 raised, and FIG. 3 shows the utility vehicle 3, 4 with the tipper body 10 lowered and locked satisfactorily. A load, for example in the form of a building material, for example gravel, which is required on a building site, is also arranged in the tipper body 10.

As is apparent, the utility vehicle 3, 4 according to FIGS. 2 and 3 also has a locking mechanism 8, 9 which has a load-carrier-side locking element 8 and a trailer-vehicle-side locking element 9. The locking element 9 is, for example, of pivotable design and is pivoted into the open position illustrated in FIG. 2 in order to release the lock. When the tipper body 10 is lowered, the locking element 9 is pivoted into a locking position in which engagement occurs behind the load-carrier-side locking element 8, and as a result the tipper body 10 is locked.

The load-carrier-side locking element 8 is securely connected to the load carrier 7, 10, and the trailer-vehicle-side locking element 9 is securely connected to the trailer vehicle 3 or the utility vehicle.

FIG. 4 shows in a schematic illustration a trailer brake system control device 1 which has an electronic control unit 2. The electronic control unit 2 carries out the described functions. The following specified input signals are fed here to signal inputs of the electronic control unit 2. The control device 1 is, in addition to the elements illustrated in FIG. 4, also connected to further components of the brake system such as, for example, a compressed air reservoir container, an electrical power supply and, if appropriate, to further sensors and operator control elements. FIG. 4 therefore only shows the components which are to be addressed for an explanation of the present invention.

An output signal I_(s) of a monitoring sensor S and a velocity signal of a velocity sensor V are fed to the control device 1 as input signals. The velocity sensor V can be, for example, a wheel speed sensor which is provided for an anti-lock brake function. The control device 1 determines the velocity of the utility vehicle 3, 4 from the velocity signal. On the output side, the control device 1 is connected to brakes B of a compressed-air-controlled brake system of the utility vehicle 3, 4. The control device 1 automatically generates a brake pressure p and outputs it to the brakes B.

The monitoring sensor V can be connected to the control device 1 either directly via an electric line or via a wireless data transmission link or a vehicle bus system such as, for example, a CAN-bus. The monitoring sensor V can also be part of another control unit or of a control device in the utility vehicle 3, 4.

FIG. 5 shows an exemplary time profile in the case of automatic activation of the brakes B of the utility vehicle as a result of detection of unsatisfactory locking of the load carrier 7, 10. Starting at a time t₀, it is assumed that an output signal I_(s) which has a value I₀, which corresponds to satisfactory locking, will firstly be output by the monitoring sensor S. Accordingly, at this time a brake pressure of p=0 will be output. At a time t₁, the monitoring sensor S outputs an output signal I_(s) which has the value I₁, which indicates unsatisfactory locking, for example due to release of the locking as a result of incorrect operator control. When triggered in this way, the control device 1 begins to output a pulsed brake pressure signal. In this context, the brake pressure p is modulated to and fro between the values p₁ and p₂. For example, p₁ is 1.2 bar and for example p₂ is 2.5 bar.

After a certain time period, at a time t₂ the brake pressure p is automatically increased further, specifically to a value p₃, which is selected such that the vehicle is significantly decelerated by activation of the brakes B. p₃ may have, for example, a value of 5 or 6 bar. The increase in the brake pressure p after the time p₂ can either take place suddenly, as illustrated by the unbroken line in FIG. 5, or gradually according to a time function, as is illustrated as an approximately linear transition function by the dot-dashed line or as illustrated as a progressive transition function by the dashed line. The time period for the transition function until the value p=p₃ is reached may be, for example, ten seconds. 

1. Method for controlling a compressed-air-controlled brake system of a utility vehicle (3, 4), wherein a monitoring sensor (S) monitors whether the securing or positioning of a vehicle part of the utility vehicle (3, 4) of a load (6) of the utility vehicle (3, 4) or of a load carrier (7, 10) which accommodates a load (6) of the utility vehicle (3, 4), provided for the sake of a safe driving state of the utility vehicle (3, 4), has occurred, and wherein the brakes (B) of the utility vehicle (3, 4) are activated automatically if the monitoring sensor (S) detects that the securing or positioning of the vehicle part, of the load (6) or of the load carrier (7, 10), provided for the sake of a safe driving state of the utility vehicle (3, 4), has not occurred, wherein at least at the start of the automatic activation of the brakes (B) of the utility vehicle (3, 4) the brakes (B) are activated in a pulsed fashion such that the brake pressure (p) is modulated to and fro between a lower pressure value (p₁) and an upper pressure value (p₂), wherein the driving utility vehicle (3, 4) is not decelerated or is only decelerated insignificantly.
 2. Method, in particular according to claim 1, for controlling a compressed-air-controlled brake system of a utility vehicle (3, 4), wherein in the driving state of the utility vehicle (3, 4) the brakes (B) of the utility vehicle (3, 4) are activated automatically, characterized in that at least at the start of the automatic activation of the brakes (B) of the utility vehicle (3, 4) the activation of the brakes (B) takes place in such a way that this activation can be perceived as a warning signal by the driver of the utility vehicle (3, 4) but the driving utility vehicle (3, 4) is not decelerated or is only decelerated insignificantly.
 3. Method according to one of the preceding claims, characterized in that in the case of automatic activation of the brakes (B) of the utility vehicle (3, 4) during a first time period (t₁ . . . t₂), at the start of the automatic activation of the brakes (B) the driving utility vehicle (3, 4) is not decelerated, or is only decelerated insignificantly, by the automatic activation of the brakes (B), and after the expiry of the first time period (t₁ . . . t₂) the driving utility vehicle (3, 4) is decelerated significantly by the automatic activation of the brakes (B).
 4. Method according to one of the preceding claims, characterized in that the automatic activation of the brakes (B), which does not, or only insignificantly, decelerates the driving utility vehicle (3, 4), is triggered at a velocity above a first minimum velocity.
 5. Method according to claim 4, characterized in that the automatic activation of the brakes (B), which significantly decelerates the driving utility vehicle (3, 4), is triggered at a velocity above a second minimum velocity which is higher than the first minimum velocity.
 6. Method according to one of the preceding claims, characterized in that the automatic activation of the brakes (B) of the utility vehicle (3, 4) is suppressed at a velocity above a third minimum velocity.
 7. Method according to claim 6, characterized in that the third minimum velocity is higher than the second minimum velocity.
 8. Method according to one of the preceding claims, characterized in that in the case of the automatic activation of the brakes (B) of the utility vehicle (3, 4) the brake pressure (p) is increased from an initial value (p₂) to a final value (p₃) with a transition function, wherein the final value (p₃) is higher than the initial value (p₂).
 9. Method according to one of the preceding claims, characterized in that the monitoring sensor (S) is arranged in or on the utility vehicle (3, 4).
 10. Method according to one of the preceding claims, characterized in that the monitoring sensor (S) monitors the satisfactory locking and/or positioning of the load carrier (7, 10), which accommodates a load (6) of the utility vehicle (3, 4), prescribed for the sake of a safe driving state of the utility vehicle (3, 4), with respect to the utility vehicle (3, 4).
 11. System composed of a brake system control device (1) for a compressed-air-controlled brake system of a utility vehicle (3, 4) and a monitoring sensor (S), which is configured to monitor whether the securing or positioning of a vehicle part of the utility vehicle (3, 4), of a load (6) of the utility vehicle (3, 4) or of a load carrier (7, 10) which accommodates a load (6) of the utility vehicle (3, 4), provided for the sake of a safe driving state of the utility vehicle (3, 4), has occurred, wherein the control device (1) has an electronic control unit (2) which is connected by a signal input to the monitoring sensor (S), and wherein the control unit (2) is configured to bring about automatic activation of the brakes (B) of the utility vehicle (3, 4) if a triggering signal (I₁) is received from the monitoring sensor (S) at the signal input, which triggering signal (I₁) indicates that the securing or positioning of the vehicle part, of the load (6) or of the load carrier (7, 10), provided for the sake of a safe driving state of the utility vehicle (3, 4), has not occurred, wherein the control unit (2) is configured in such a way that, at least at the start of the automatic activation of the brakes (B) of the utility vehicle (3, 4), the brakes (B) are activated in a pulsed fashion such that the brake pressure (p) is modulated to and fro between a lower pressure value (p₁) and an upper pressure value (p₂), wherein the driving utility vehicle (3, 4) is not decelerated or is only decelerated insignificantly.
 12. System according to claim 11, characterized in that the monitoring sensor (S) is embodied as a locking sensor which is configured to monitor the locking of a vehicle part of the utility vehicle (3, 4), of a load (6) of the utility vehicle (3, 4) or of a load carrier (7, 10) which accommodates a load (6) of the utility vehicle (3, 4), provided for the sake of a safe driving state of the utility vehicle (3, 4).
 13. Brake system control device for a system according to one of claims 11 to 12, wherein the electronic control unit (2) of the control device (1) is configured to bring about the automatic activation of the brakes (B) of the utility vehicle (3, 4).
 14. Brake system control device according to claim 14, wherein the electronic control unit (2) of the control device (1) is configured to carry out a method according to one of claims 1 to
 10. 15. Control unit (2) for carrying out the method according to one of claims 1 to
 10. 